U.S. patent application number 12/043730 was filed with the patent office on 2008-09-11 for printer and printing method.
This patent application is currently assigned to MIMAKI ENGINEERING CO, LTD.. Invention is credited to Nobuyuki Ono, Kazutomo Seki, Chikao TEZUKA.
Application Number | 20080218542 12/043730 |
Document ID | / |
Family ID | 39493400 |
Filed Date | 2008-09-11 |
United States Patent
Application |
20080218542 |
Kind Code |
A1 |
TEZUKA; Chikao ; et
al. |
September 11, 2008 |
PRINTER AND PRINTING METHOD
Abstract
A printer includes a holding unit, a printer head, a movement
controller and a printing controller. The holding unit is
configured to hold a print substrate having a surface to be
printed. The printer head is configured to eject ink from a
plurality of ejection nozzles to the surface. The movement
controller is configured to move the holding unit and the printer
head relative to each other. The printing controller is configured
to control ejection of the ink from the printer head according to a
surface curvature of the surface and a relative position of the
holding unit and the printer head.
Inventors: |
TEZUKA; Chikao; (Tomi-city,
JP) ; Seki; Kazutomo; (Tomi-city, JP) ; Ono;
Nobuyuki; (Nagano-shi, JP) |
Correspondence
Address: |
DITTHAVONG MORI & STEINER, P.C.
918 Prince St.
Alexandria
VA
22314
US
|
Assignee: |
MIMAKI ENGINEERING CO, LTD.
Tomi-city
JP
|
Family ID: |
39493400 |
Appl. No.: |
12/043730 |
Filed: |
March 6, 2008 |
Current U.S.
Class: |
347/8 |
Current CPC
Class: |
B41J 3/4073 20130101;
B33Y 30/00 20141201 |
Class at
Publication: |
347/8 |
International
Class: |
B41J 25/308 20060101
B41J025/308 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 9, 2007 |
JP |
2007-059385 |
Claims
1. A printer comprising: a holding unit configured to hold a print
substrate having a surface to be printed; a printer head configured
to eject ink from a plurality of ejection nozzles to the surface; a
movement controller configured to move said holding unit and said
printer head relative to each other; and a printing controller
configured to control ejection of the ink from the printer head
according to a surface curvature of the surface and a relative
position of said holding unit and said printer head.
2. The printer according to claim 1, wherein said printing
controller is configured to control a number of ejection nozzles
which actually eject ink.
3. The printer according to claim 1, wherein said printing
controller is configured to control ejection speed and/or an
ejection amount of the ink ejected from said plurality of ejection
nozzles according to the surface curvature of the surface.
4. The printer according to claim 1, wherein said movement
controller is configured to move the holding unit and the printer
head relatively so that a distance between the plurality of
ejection nozzles and the surface to be printed is kept at a
predetermined distance and so that the ink ejected from the
plurality of ejection nozzles collides with the surface
substantially perpendicularly.
5. The printer according to claim 1, wherein said printing
controller is configured to control the ejection of the ink from
the printer head according to a distance between the plurality of
ejection nozzles and the surface to be printed.
6. The printer according to claim 1, wherein the printing
controller is configured to control speed of the ink ejected from
the printer head according to a distance between the plurality of
ejection nozzles and the surface to be printed.
7. The printer according to claim 1, wherein the printing
controller is configured to control a size of ink droplet ejected
from the printer head according to a distance between the plurality
of ejection nozzles and the surface to be printed.
8. The printer according to claim 1, wherein the printing
controller is configured to control the printer head to eject ink
if a distance between the plurality of ejection nozzles and the
surface to be printed is within a predetermined range.
9. The printer according to claim 1, wherein the printing
controller is configured to increase a speed of the ink ejected
from the printer head as a distance between the plurality of
ejection nozzles and the surface to be printed increases.
10. The printer according to claim 1, wherein the printing
controller is configured to increase an amount of ink to be ejected
from the printer head as a distance between the plurality of
ejection nozzles and the surface to be printed increases.
11. The printer according to claim 1, wherein a supporting device
supports said holding unit and said printer head such that said
holding unit and said printer head are movable relative to each
other in directions of axes X, Y, and Z which are substantially
perpendicular to each other, said holding unit being rotatable
about the axis X and the axis Y relative to said printer head, and
wherein said movement controller is configured to control said
holding unit and said printer head to move relative to each other
in the direction of said axes X, Y, and Z and control said holding
unit to rotate about said axis X and said axis Y relative to said
printer head.
12. The printer according to claim 11, wherein said supporting
device comprises, a first supporting member supported on a base
such that said first supporting member is movable in the direction
of the axis X extending in a horizontal plane direction, a second
supporting member supported on said first supporting member such
that said second supporting member is movable in the direction of
the axis Z extending in a direction substantially perpendicular to
said horizontal plane direction, and a third supporting member
supported on said second supporting member such that said third
supporting member is rotatable about a first rotation axis
extending in the direction of the axis Y substantially
perpendicular to the directions of said axis X and said axis Z,
wherein said holding unit is supported on said third supporting
member such that the holding unit is rotatable about a second
rotation axis extending in a plane substantially perpendicular to
the first rotation axis to hold the print substrate; and wherein
said printer head is disposed on said base to extend above the
print substrate, held by said holding unit, such that said printer
head is movable in the direction of the axis Y.
13. The printer according to claim 1, wherein the surface to be
printed has a three-dimensional surface.
14. A printer comprising: holding means for holding a print
substrate having a surface to be printed; printer head means for
ejecting ink from a plurality of ejection nozzles to the surface;
movement controller means for moving said holding means and said
printer head means relative to each other; and printing controller
means for controlling ejection of the ink from the printer head
means according to a surface curvature of the surface and a
relative position of said holding means and said printer head
means.
15. A printing method comprising: holding a print substrate having
a surface to be printed; ejecting ink from a plurality of ejection
nozzles to the surface; moving said print substrate held and said
plurality of ejection nozzles relative to each other; and
controlling ejection of the ink from the plurality of ejection
nozzles according to a surface curvature of the surface and a
relative position of said print substrate held and said plurality
of ejection nozzles.
16. A three-dimensional printer comprising: a holding unit
configured to hold a print substrate having a three-dimensional
surface to be printed; a printer head configured to eject ink from
a plurality of ejection nozzles to the three-dimensional surface; a
movement controller configured to move said holding unit and said
printer head relative to each other; and a printing controller
configured to control ejection of the ink from the printer head
according to a surface curvature of the three-dimensional surface
and a relative position of said holding unit and said printer head.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims priority under 35 U.S.C.
.sctn.119 to Japanese Patent Application No. 2007-059385, filed
Mar. 9, 2007, entitled "Three-demensional Printer." The contents of
this application are incorporated herein by reference in their
entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a printer, a printing
method and a three-dimensional printer.
[0004] 2. Discussion of the Background
[0005] A various printers for printing characters, figures, and the
like on a print substrate such as paper are conventionally known.
As an example, a printer connected to a computer to perform a
printing on a paper has been widely used for business purposes and
household purposes. Typical conventional printer is of a style of
printing while feeding a paper or a sheet member as a print
substrate in a predetermined feeding direction and moving a printer
head thereof in a scanning direction perpendicular to the feeding
direction. JP-A-2003-191455 and JP-A-2004-148666 disclose such
printers. The contents of these publications are incorporated
herein by reference in their entirety.
[0006] The conventional printers are of a type of performing
predetermined printing on a planate sheet material or a flat
surface of a solid object, that is, of a type for performing
two-dimensional printing. Recently, however, there is a need for a
printer capable of performing a printing on an object having a
three-dimensional surface (for example, a cylindrical surface, a
spherical surface, and other various curved surfaces).
SUMMARY OF THE INVENTION
[0007] According to one aspect of the present invention, a printer
includes a holding unit, a printer head, a movement controller and
a printing controller. The holding unit is configured to hold a
print substrate having a surface to be printed. The printer head is
configured to eject ink from a plurality of ejection nozzles to the
surface. The movement controller is configured to move the holding
unit and the printer head relative to each other. The printing
controller is configured to control ejection of the ink from the
printer head according to a surface curvature of the surface and a
relative position of the holding unit and the printer head.
[0008] According to another aspect of the present invention, a
printing method includes holding a print substrate having a surface
to be printed, ejecting ink from a plurality of ejection nozzles to
the surface, moving said print substrate held and said plurality of
ejection nozzles relative to each other, and controlling ejection
of the ink from the plurality of ejection nozzles according to a
surface curvature of the surface and a relative position of said
print substrate held and said plurality of ejection nozzles.
[0009] According to further aspect of the present invention, a
three-dimensional printer includes a holding unit, a printer head,
a movement controller and a printing controller. The holding unit
is configured to hold a print substrate having a three-dimensional
surface to be printed. The printer head is configured to eject ink
from a plurality of ejection nozzles to the three-dimensional
surface. The movement controller is configured to move the holding
unit and the printer head relative to each other. The printing
controller is configured to control ejection of the ink from the
printer head according to a surface curvature of the
three-dimensional surface and a relative position of the holding
unit and the printer head.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] A more complete appreciation of the invention and many of
the attendant advantages thereof will be readily obtained as the
same becomes better understood by reference to the following
detailed description when considered in connection with the
accompanying drawings, wherein:
[0011] FIG. 1 is a schematic illustration for explaining the
operation principle of a printer according to an embodiment of the
present invention;
[0012] FIG. 2 is a front view of a printer according to an
embodiment of the present invention;
[0013] FIG. 3 is a side view of the printer shown in FIG. 2;
[0014] FIG. 4 is a perspective view showing a part of the printer
shown in FIG. 2;
[0015] FIG. 5 is a schematic side view illustrating the relation
between a printer head and a print substrate in the printer shown
in FIG. 1; and
[0016] FIG. 6 is a schematic side view for explaining the control
for ink ejection from the printer head in case of a print substrate
having a curved surface.
DESCRIPTION OF THE EMBODIMENTS
[0017] The embodiments will now be described with reference to the
accompanying drawings, wherein like reference numerals designate
corresponding or identical elements throughout the various
drawings.
[0018] First, control of relative movement between a print
substrate 80 held by a holding unit and a printer head 85 and
control of printing in the printer according to an embodiment of
the present invention will be briefly described with reference to
FIG. 1. The print substrate 80 in FIG. 1 is a member having, for
example, a truncated cone shape. Ink is ejected from the printer
head (inkjet head) 85 to an outer surface 81 of the truncated cone
shape to perform intended printing on the surface. FIG. 1 will be
used for describing the operation principle of the printer having
the aforementioned arrangement.
[0019] The printer has a supporting device for supporting the print
substrate 8O, but not shown. The supporting device supports the
print substrate 80 in such a manner that the central axis X of the
truncated cone extends in an anteroposterior direction, the print
substrate 80 is rotatable about the axis X (i.e. rotatable in the
direction shown by an arrow A), in addition to this state, the
print substrate 80 is rotatable about an axis Y extending in a
lateral direction perpendicular to the axis X and passing through a
point O1 on the axis X (i.e. rotatable in the direction shown by an
arrow B), the print substrate 80 is also movable anteroposteriorly
along the direction of the axis X (i.e. movable in the direction
shown by an arrow D(x)), and further the print substrate 80 is
movable vertically along an axis Z extending in a vertical
direction perpendicular to the axis X and the axis Y (i.e. movable
in the direction shown by an arrow D(z)). The printer head is
arranged above the print substrate 80 supported in the
aforementioned manner by the supporting device (not shown) in such
a manner that the printer head is movable in the directions of the
axis Y (i.e. movable in the direction shown by an arrow D(y)). The
printer head 85, which is provided with a plurality of ink nozzles
formed in a bottom thereof, ejects ink supplied from an ink
supplier (not shown) in a state that the ink nozzles are each
controlled by a printing controller to perform predetermined
printing on the surface 81 of the print substrate 80.
[0020] To perform the intended printing on the conical surface 81
of the print substrate 80, supported by the supporting device, by
ejecting the ink through the ink nozzles formed in the bottom of
the printer head 85, it is necessary to bring the ink nozzles to a
position, close to the print substrate 80, facing the surface to be
printed of the print substrate 80 and having a predetermined
printing distance from the surface to be printed of the print
substrate 80 (i.e. a position having an optimum distance for the
printing performed by ejecting the ink from the ink nozzles to
adhere to the surface 81). It is also necessary to set the ink
nozzles formed in the bottom of the printer head 85 such that the
ink nozzles fully face the surface to be printed, that is, the
ejecting direction of the ink from the ink nozzles becomes
substantially perpendicular to the surface 81 so that ejected ink
collides with the surface 81 substantially perpendicularly.
[0021] For example, in case of ejecting ink from the printer head
85 to a point P0 in FIG. 1 on the surface of the print substrate 80
to perform the printing on the point P0, it is necessary to bring
the surface at the point P0 to the position where is spaced apart
from the bottom 86 of the printer head 85 just by a predetermined
printing distance CL0 and to make the surface of the print
substrate 80 at the point P0 substantially parallel to the bottom
86 of the printer head. The predetermined printing distance CL0 is
a value as a distance enabling optimum printing on the surface of
the print substrate 80 according to the size and the speed
(momentum) of ink droplets ejected through the plural ink nozzles
formed in the bottom 86 of the printer head to face downward. In
other words, a printing controller controls ejection of the ink
from the plural ink nozzles according to a surface curvature of the
surface to be printed and a relative position of said holding unit
and said printer head.
[0022] For this, from the state that the print substrate 80 is
supported as shown in FIG. 1, the print substrate 80 is moved
anteroposteriorly along the direction of the axis X (i.e. moved in
the direction shown by the arrow D(x)) and the print substrate 80
is rotated about the axis X (i.e. rotated in the direction shown by
the arrow A) until the print point P0 becomes the top of the print
substrate 80 and the print point P0 reaches a position directly
below the printer head 85. Then, the print substrate 80 is rotated
about the axis Y (i.e. rotated in the direction shown by the arrow
B) until the ridge line L1 passing through the print point P0
extends horizontally, the printer head 85 is moved along the
direction of the axis Y (i.e. moved in the direction shown by the
arrow D(y)) until the bottom 86 (nozzles for ejecting ink) of the
printer head 85 reaches to a position directly above the print
point P0, and the print substrate 80 is moved upward along the
direction of the axis Z (moved in the direction of the arrow D(z))
until the bottom 86 (nozzles for ejecting ink) of the printer head
85 reaches a position, close to the print point P0, having just the
predetermined printing distance from the print point P0. It should
be noted that the moving and rotating order is not limited unless
the print substrate 80 and the printer head 85 interfere each
other.
[0023] The print substrate 80 is rotated about the axis X and the
axis Y for the aforementioned movement. The rotational axis X and
the rotational axis Y both pass through the point O1 as mentioned
above. The point O1 is set to be positioned inside the print
substrate 80 supported by the supporting device. As a result of
this, the print substrate 80 is adapted to rotate about the axis X
and the axis Y passing through the point O1. Therefore, when the
print substrate 80 is controlled to move relative to the printer
head 85 while maintaining the state that the print substrate 80
faces the bottom 86 of the printer head 85 and is spaced apart from
the bottom 86 of the printer head 85 by the predetermined printing
distance, the moving range of the print substrate 80 can be narrow
so that the supporting device for supporting the print substrate 80
can be made to have a compact structure. Similarly, since the
moving range of the printer head 85 can be narrow, the printer head
85 can be made to have a compact structure, thereby making the
entire printer to have a compact structure.
[0024] In the state where the printer head 85 and the print
substrate 80 are positioned such that the bottom 86 (nozzles for
ejecting ink) of the printer head 85 is spaced apart from the print
point P0 by the predetermined printing distance CL0 and the bottom
86 and the print point P0 are squarely faced to each other as shown
in FIG. 5, ink is ejected through the nozzles of the bottom 86 of
the printer head 85, as shown by arrows in FIG. 5, according to the
control by the printing controller to perform printing on an area
along the print point P0 (area along the ridge line L1 passing
through the print point P0). For example, to print along a
circumferential direction on the surface of the print substrate 80,
the printing controller controls to change the aforementioned
position for supporting the print substrate 80 by the supporting
device while maintaining such a positional relation that each of
points P1, P2, P3 . . . along the circumferential direction on the
outer surface of the print substrate 80 is squarely faced to the
bottom 86 (nozzles for ejecting ink) of the printer head 85 and is
spaced by the predetermined printing distance CL0.
[0025] In the case of the print substrate 80 having a truncated
cone shape as mentioned above, the control is conducted to eject
ink through all of the ink nozzles while maintaining the bottom 86
formed with a plurality of ink nozzles of the printer head 85 to
extend parallel with the ridge line L1 and spaced apart form the
ridge line L1 by the predetermined printing distance CL0 as shown
in FIG. 5. Accordingly, excellent printing along the ridge line L1
and over a wide area corresponding to the width of the printer head
85 is conducted.
[0026] However, in case of a print substrate 80' having a curved
surface 81' as shown in FIG. 6, the distance between the bottom 86
of the printer head 85 and the surface L2 facing the bottom 86 is
not constant and varies. In this case, some portions (areas) of the
surface L2 may not set to have the predetermined printing distance
CL0 relative to the bottom 86. For this case, it is controlled such
that the portion (area) facing the center of the bottom of the
printer head 85 is positioned in an allowable range of the
predetermined printing distance CL0, i.e. a range at least CL1
(=CL0-.alpha.) and at most CL2 (=CL0+.alpha.) and that only some of
the nozzles in a region corresponding to the aforementioned portion
(area) eject ink. For example, in a state that the print substrate
80' is positioned relative to the printer head 85 as shown in FIG.
6, ink ejection nozzles only in a bottom region Al of the printer
head 85 corresponding to a portion (area) within the allowable
range of the predetermined printing distance CL0 of at least CL1
and at most CL2 are controlled to eject ink and ink ejection
nozzles in both side regions B1, B2 are controlled not to eject
ink. In other words, a printing controller controls ejection of the
ink from the plural ink nozzles according to a surface curvature of
the surface to be printed and a relative position of said holding
unit and said printer head. Therefore, printing is conducted only
on a portion (area) of which printing distance is in the range
enabling the optimum printing can be performed on the surface of
the print substrate 80', thereby conducting excellent printing
control without deteriorating the printing quality.
[0027] In stead of the ink ejection control within the allowable
range of the printing distance as mentioned above, the amount and
speed of ink ejection in the regions B1, B2 out of the allowable
range of the predetermined printing distance CL0 of at least CL1
and at most CL2 may be controlled according to actual distances not
to deteriorate the printing quality by the ink ejection in the
regions B1, B2. For example, the ink ejection amount may be
increased or the ink ejection speed may be increased according to
increase in the distance from the bottom 86 of the printer head 85
so as to overcome the adverse affect by increase of the distance
and to maintain the printing quality.
[0028] A concrete example arrangement of a printer capable of
performing the three-dimensional printing according to the
operation principle as described above will be described with
reference to FIG. 2 through FIG. 4. This printer has a base 1 and a
gate-like supporting frame 2. The gate-like supporting frame 2 is
fixed on the base 1 and comprises a pair of left and right
supporting legs 2a, 2b and a supporting beam 2c connecting the
upper ends of the supporting legs 2a, 2b and extending in a lateral
direction. The printer also has a first controller 6 with an
operator control panel 6a which is adjacent to the right supporting
leg 2b and a second controller 7 with a maintenance station 8 which
is adjacent to the left supporting leg 2a. The first and second
controllers 6, 7 comprise various controllers such as a movement
controller for controlling the movement and rotation of the
respective components as will be described later, a printing
controller for controlling the ejection of ink from the printer
head, and a power controller.
[0029] A pair of front and rear lateral guide rails 3a, 3b are
mounted to extend in the lateral direction (direction of the axis
Y) on the upper surface of the supporting beam 2c and a printer
head carriage 4 is mounted on the lateral guide rails 3a, 3b such
that the printer head carriage 4 is movable in the lateral
direction (i.e. movable in the direction shown by arrow D(y)). To
allow the movement of the printer head carriage 4 in the lateral
direction, a traveling mechanism such as a ball screw mechanism is
provided. By controlling the driving of the traveling mechanism,
the lateral movement of the printer head carriage 4 can be
controlled. Since such traveling mechanism is well known in the
art, the description of the structure will be omitted.
[0030] The printer head carriage 4 is a member which extends
forward from a portion supported by the lateral guide rails 3a, 3b,
is bent downward, and extends forward again, that is, the printer
head carriage 4 has a crank shape as seen from a side. Mounted on a
front end portion 4a of the printer head carriage 4 is a plurality
of printer head modules 5. The printer head modules 5, also called
inkjet head modules, are each provided with a number of ink nozzles
formed in the bottom thereof and, for example, eject respective
inks of different colors from the ink nozzles. The control of ink
ejection is conducted by the printing controller for every ink
nozzle. Since such control is conventionally well known in the art,
the description of the structure will be omitted.
[0031] The printer head carriage 4 with the printer head modules 5
is movable along the lateral guide rails 3a, 3b in the lateral
direction. In a state that the printer head carriage 4 is at the
leftmost position as shown in FIG. 2, the maintenance station 8 is
moved upward to prevent the ink nozzles in the bottoms of the
printer head modules 5 from being dried and to clean the ink
nozzles.
[0032] A pair of anteroposterior guide rails 1a, 1b extending in
the anteroposterior direction (direction of the axis X) are
arranged on the base 1 between the left and right supporting legs
2a, 2b of the gate-like supporting frame 2. A first supporting
member 10 is mounted such that the first supporting member 10 is
movable along the anteroposterior guide rails 1a, 1b in the
anteroposterior direction (i.e. movable in the direction shown by
the arrow D(x)). To allow the movement of the first supporting
member 10 in the anteroposterior direction, a traveling mechanism
such as a ball screw mechanism is provided. By controlling the
driving of the traveling mechanism, the anteroposterior movement of
the first supporting member 10 can be controlled. Since such
traveling mechanism is well known in the art, the description of
the structure will be omitted.
[0033] A vertical supporting member 11 is fixed in a vertically
standing state on the first supporting member 10. Attached to the
front surface of the vertical supporting member 11 are a pair of
vertical guide rails 12a, 12b extending in the vertical direction
(the direction of the axis Z). A second supporting member 15 is
mounted to and supported by the vertical guide rails 12a, 12b such
that the second supporting member 15 is movable in the vertical
direction (i.e. movable in the direction shown by the arrow D(z)).
To allow the movement of the second supporting member 15 in the
vertical direction, a traveling mechanism such as a ball screw
mechanism is provided. By controlling the driving of the traveling
mechanism, the vertical movement of the second supporting member 15
can be controlled. Since such traveling mechanism is well known in
the art, the description of the structure will be omitted.
[0034] The front surface 15a of the second supporting member 15 is
formed into a semicylindrical shape of which center is a first
rotation axis Y0 extending in the direction of the axis Y passing
through a prescribed point O1 (a point set to a position where the
print substrate 80 will be positioned as will be described later)
defined relative to the second supporting member 15. A third
supporting member 20 has a rear surface 20a having a
semicylindrical shape corresponding to the semicylindrical shape of
the front surface 15a. The third supporting member 20 is disposed
slidably along the front surface 15a. That is, the rear surface 20a
of the third supporting member 20 is movable and slidable relative
to the front surface 15a of the second supporting member 15,
thereby allowing the third supporting member 20 to rotate about the
first rotation axis Y0 relative to the second supporting member 15
(i.e. rotate in the direction shown by the arrow B). According to
this structure, the first rotation axis Y0 as the center of
rotation of the third supporting member 20 is positioned in a
hollow space inside the third supporting member 20 so that the
print substrate 80 can be supported in the hollow space. That is,
the first rotation axis Y0 is located at a position passing through
the print substrate 80.
[0035] To move the third supporting member 20 to rotate about the
first rotation axis Y0 relative to the second supporting member 15,
the third supporting member 20 is provided with internal teeth 21
which are formed in a front surface of a left-side portion, in FIG.
2, thereof and of which center is the first rotation axis Y0. A
driving motor 16 is mounted on a front surface of a left-side
portion of the second supporting member 15 and is provided with a
driving pinion 17 attached to a driving shaft thereof. The driving
pinion 17 is meshed with the internal teeth 21. As the driving
pinion 17 is driven to rotate by the driving motor 16, the internal
teeth 21 meshed with the driving pinion 17 are driven to rotate,
thereby rotating the third supporting member 20 about the first
rotation axis Y0.
[0036] A holding shaft 25 extends in the anteroposterior direction
(the direction of the axis X) and projects forward from the front
surface of the third supporting member 20 in such a manner that the
holding shaft 25 is rotatable about a second rotation axis X0
passing through the aforementioned prescribed point O1. A holding
chuck 26 for holding the print substrate is attached to the front
end of the holding shaft 25. The holding shaft 25 is driven to
rotate by a driving motor (not shown) which is disposed within the
third supporting member 20 and the holding chuck 26 has a structure
capable of holding the print substrate 80. As the holding shaft 25
is driven to rotate with the print substrate 80 held by the holding
chuck 26, the print substrate 80 is rotated about the second
rotation axis X0. As can be understood from this, the second
rotation axis X0 is located at a position passing through the print
substrate 80.
[0037] The second rotation axis X0 extends in the anteroposterior
direction (the direction of the axis X) when the third supporting
member 20 is positioned at a predetermined rotational position (the
rotational position shown in FIG. 3). Since the third supporting
member 20 is rotatable about the first rotation axis Y0 as
mentioned above, the second rotational axis X0 is inclined upward
or downward according to the rotational position of the third
supporting member 20. Accordingly, the print substrate 80 is moved
to rotate. Though the first rotation axis Y0 and the second
rotation axis X0 both pass the prescribed point O1 and intersect
with each other in the illustrated example, these may not intersect
with each other, that is, may be shifted from each other. However,
the first rotation axis Y0 and the second rotation axis X0
preferably intersect with each other because the position
calculation of the print substrate 80 is facilitated and the
control by the movement controller is facilitated.
[0038] In the printer having the aforementioned structure, the
second rotation axis X0 as the rotation center of the holding shaft
25 corresponds to the axis X in the arrangement for explaining the
operation principle shown in FIG. 1 and the first rotation axis Y0
as the rotation center of the third supporting member 20
corresponds to the axis Y in the arrangement for explaining the
operation principle shown in FIG. 1. The second supporting member
15 supporting the third supporting member 20 is supported by the
first supporting member 10 in such a manner as to allow the second
supporting member 15 to move in the direction of the axis Z (the
vertical direction) (i.e. to move in the direction shown by the
arrow D(z)) and the first supporting member 10 is supported on the
base 1 in such a manner as to allow the first supporting member 10
to move in the direction of the axis X (the anteroposterior
direction) (i.e. to move in the direction shown by the arrow D(x)).
In addition, the printer head is supported above the print
substrate 80 in such a manner as to allow the printer head to move
in the direction of the axis Y (the lateral direction) relative to
the base 1 (i.e. to move in the direction shown by the allow D(y)).
That is, the printer is adapted to perform the same actions as
those explained in the operation principle as shown in FIG. 1.
[0039] As apparent from the above description, the printer as shown
in FIG. 2 through FIG. 4 can perform the intended printing by
ejecting ink from the ink nozzles formed in the bottom of the
printer head modules 5 onto the surface 81 of the print substrate
80 according to the operation principle explained with reference to
FIG. 1. Though an example in which the printing is performed on the
surface of the print substrate 80 having a truncated cone shape has
been explained with reference to FIG. 1, the configuration of the
print substrate is not limited thereto and the printing can be
performed on any curved surface including a cylindrical surface and
a spherical surface. In this case, ejection control is conducted to
obtain excellent printing quality regardless of any curvature by
changing the region of nozzles to be used among a plurality of
nozzles of the printer head and/or controlling the ejection amount
and/or ejection speed of ink ejected from the nozzles.
[0040] Though the first rotation axis Y0 and the second rotation
axis X0 intersect with each other at the prescribed point O1 in
this printer, the prescribed point O1 is located at a position
passing through the print substrate 80 held by the holding chuck
26, that is, a position in a hollow space inside the printer. By
rotating the third supporting member 20 about the first rotation
axis Y0 and rotating the holding chuck 26 about the second rotation
axis X0, the print substrate 80 is moved to rotate about the
prescribed point O1. Accordingly, the moving range of the print
substrate 80 can be reduced to the minimum. This enables a printer
having a small (compact) structure and enables easy operation
control.
[0041] According to the printer having the aforementioned
structure, the holding unit and the printer head are controlled to
move relative to each other in the three-dimensional space by the
movement controller and, during this, the ink ejection from the
printer head is controlled by the printing controller according to
the controlled movement of the holding unit and the printer head,
thereby easily and automatically performing the intended printing
on the surface of the print substrate having a three-dimensional
profile. During this, the movement controller is adapted to control
the aforementioned relative movement while maintaining a positional
relation between said printer head and said print substrate held by
the holding unit such that ink nozzles of the printer head and a
portion to be printed of the print substrate face each other and
are spaced apart from each other by the predetermined printing
distance and that ink ejected from said ink nozzles perpendicularly
collides with the surface of the portion to be printed, thereby
enabling the most effective ejection of ink from the ink nozzles to
apply the ink to the portion to be printed on the surface of the
print substrate and thus enabling precise and excellent printing
relative to a three-dimensional surface.
[0042] Obviously, numerous modifications and variations of the
present invention are possible in light of the above teachings. It
is therefore to be understood that within the scope of the appended
claims, the invention may be practiced otherwise than as
specifically described herein.
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